Intelligent switching system for voice and data

ABSTRACT

A teleconferencing system for voice and data provides interconnections among user sites via a central station. User stations at user sites each alternate operation between a data mode connecting a user computer and modem to a user telephone communication path and a voice mode connecting a telephony circuit to the communication path. The teleconferencing system is adapted for conducting a voice conference over standard telephone lines while allowing simultaneous viewing of data objects such as slides, graphs, or text. A host computer connected to the central station serves as a central repository for storage and retrieval of data objects for use in teleconferences.

RELATED APPLICATIONS

This application is a continuation of Ser. No. 11/567,842, filed on Dec.7, 2006; which is a continuation of Ser. No. 10/805,795, filed on Jun.17, 2004, now U.S. Pat. No. 7,215,752; which is a continuation of Ser.No. 10/000,634, filed on Oct. 31, 2001, now U.S. Pat. No. 6,819,752;which is a continuation of Ser. No. 09/567,854, filed on May 9, 2000,now U.S. Pat. No. 6,373,936; which is a continuation of Ser. No.09/203,110, filed on Nov. 30, 1998, now U.S. Pat. No. 6,061,440; whichis a continuation of Ser. No. 08/390,396, filed Feb. 16, 1995, now U.S.Pat. No. 5,844,979. The entire teachings of these applications areincorporated herein by reference.

BACKGROUND OF THE INVENTION

During a voice teleconference, it is often desirable for two or moreconference participants to be able to both view and discuss common dataobjects such as a set of images. For example, one participant may desireto conduct a slide presentation concurrent with a voice conversationamong the participants. Systems which enable a person to receive andview image data over a telephone line concurrent with voice conversationare known. One such system interrupts the telephone conversationmomentarily to allow visual data to be transmitted over the telephoneline. Following the transmission of visual data, the voice communicationcan be automatically resumed. Other known systems for sharing voice andimage data generally require relatively complex equipment, speciallyenhanced modems, or dedicated high speed digital lines such as InternalServices Digital Network. Still other systems require multiple telephonelines to handle both data object manipulation and voice. Generally, theknown desktop teleconferencing systems are for point-to-pointcommunications rather than multipoint, multiparty communications.

SUMMARY OF THE INVENTION

It would be advantageous to provide a teleconferencing system whichavoids having to interrupt voice communication in order to transmit dataobjects such as images meant to be viewed and discussed concurrently. Itwould also be advantageous to be able to provide such a teleconferencingcapability without requiring complex devices or dedicated lines. Theabove and other advantages are achieved by the present invention. Ingeneral, the teleconferencing provided by the present invention allowsmultiple users to conduct a voice conference over standard telephonelines while simultaneously viewing shared slides, graphs, text, or otherdata objects.

The improved teleconferencing system stores a common set of dataobjects, such as slides, in a digital computer associated with eachparticipant prior to the start of a voice conference. Once a voiceconference is underway, a lead speaker can generate audible signals(e.g., Dual Tone Multi-frequency (DTMF) tones) to which the computersrespond to coordinate simultaneous display of the data objects on eachparticipant's computer screen. Since the data objects are stored priorto the conference and the audible signals are sent with voicecommunications signals, the voice conversation can flow naturally anduninterrupted by data transmissions.

To facilitate storage and dissemination of the common data objects, anovel arrangement is employed whereby a host computer, preferablyconfigured as a bulletin board system (BBS), serves as a centralrepository for collecting subsets of data objects from conferenceparticipants and combining the subsets into a common set prior to aconference. Participating speakers each initially connect to the hostcomputer and transmit a subset of data objects to the host computer.Participants (speakers and conference attendees) in turn are able toretrieve the common set of data objects from the BBS host computerbefore entering into a voice conference.

The host computer connects to a central station having a crosspointswitching matrix for interconnecting participants, or users, intomultipoint voice conferences. The participants connect to the centralstation over standard telephone lines. An inexpensive user stationcontrolled by the participant's digital computer facilitates selectionbetween voice and data modes of access to the central station and thehost computer. A participant can generate and receive audible signalsvia the user station to control conference and switching actions inrelation to the user station and the central station. For example, aparticipant can generate an audible signal which switches theparticipant's user station from a voice mode to a data mode andconcurrently reconfigures the central station to connect the participanteither to the BBS host computer or to another participant for data modeoperation.

Accordingly, a voice/data teleconferencing system interconnects aplurality of user sites and a central site over a plurality ofcommunication paths, such as telephone lines. Each user site may includea user digital computer connectable to a user modem for transmitting andreceiving data signals. A host digital computer at the central site isconnectable to a plurality of host modems for transmitting and receivingdata signals to and from the user sites.

A user station located at each user site includes a data portconnectable to a user modem, a telephony circuit capable of transmittingand receiving voice communications signals, and a mode selector foralternately connecting the data port and the telephony circuit to acommunication path. The mode selector has a data mode position in whichthe data port is connected to the communication path and a voice modeposition in which the telephony circuit is connected to thecommunication path and the data port is connected to a user modemloopback impedance. The mode selector is responsive to a selectorcontrol signal to switch from data mode to voice mode, and the selectordefaults to the data mode in the absence of the selector control signal.Thus, in the data mode, data signals can pass between the data port andthe communication path, and in the voice mode, voice communicationssignals can pass between the telephony circuit and the communicationpath while the user modem is held “off-hook” by the loopback impedance.The user digital computer is programmed to control the user station.

The user station further includes a tone generator and tone detector forrespectively transmitting and receiving audible conferencing signalswith the voice communications signals over the communication path.

A central station at the central site includes a plurality of line portsand a switching matrix for interconnecting the user stations. Theswitching matrix comprises a plurality of crosspoint switching elements,each switching element actuable to connect one line port to another lineport in response to matrix control signals. The central station furtherincludes a plurality of tone generators and tone detectors coupled torespective line ports for transmitting and receiving audibleconferencing signals to and from user stations.

The central station further includes a plurality of computer portsconnectable to respective host modems. The central station includescentral selector means for alternately connecting a line port and a hostmodem loopback impedance to a respective computer port. The centralselector means has a pass-through position in which the line port isconnected to the computer port and a loopback position in which the hostmodem loopback impedance is connected to the computer port. The centralselector means responds to central selector control signals to switchfrom a pass-through position to a loopback position and defaults to thepass-through position in the absence of central selector controlsignals, such that in the pass-through position, data signals can passbetween a line port and a respective computer port.

The central station further includes a controller for controllingconference and switching actions in the central station.

According to another aspect of the invention, each user site can recordaudible conferencing signals and voice communications signals in a voiceconference for playing back at a subsequent time in conjunction withsimultaneous display of the data objects on the user computer screen.

The above and other features of the invention including various noveldetails of construction and combinations of parts will now be moreparticularly described with reference to the accompanying drawings andpointed out in the claims. It will be understood that the particularteleconferencing system embodying the invention is shown by way ofillustration and not as a limitation of the invention. The principlesand features of this invention may be employed in varied and numerousembodiments without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the teleconferencing system of the presentinvention.

FIG. 2 is a schematic circuit diagram of the user station shown in FIG.1.

FIG. 3 is a schematic block diagram of the central station shown in FIG.1.

FIG. 4 is a circuit diagram of the switching arrangement for connectinga line port to the switching matrix shown in FIG. 3.

FIG. 5 is a representation diagram of the reception area view of theuser interface displayed on computer screen CS1 shown in FIG. 1.

FIG. 6 is a representation diagram of the conference room view of theuser interface displayed on computer screen CS1 shown in FIG. 1.

FIG. 7 is a representation diagram of the overhead view of the userinterface displayed on computer screen CS1 shown in FIG. 1.

FIG. 8 is a representation of the format used for audible conferencecontrol signals.

FIG. 9 is a flow chart of the user station activation procedure.

FIG. 10 is a flow chart of the procedure for switching to voice modeduring a conference.

FIG. 11 is a flow chart of the procedure for controlling simultaneousviewing of slides in a conference.

FIG. 12 is a flow chart of the procedure for conducting a whiteboardsession in a conference.

FIG. 13 is a flow chart of the procedure for leaving a conference.

FIG. 14 is a block diagram of a networking arrangement ofteleconferencing systems of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In general, the teleconferencing provided by the present inventionallows multiple users to conduct a voice conference while simultaneouslyviewing distributed slides, graphs, text, or other data objects. Shownin FIG. 1 is a block diagram of a preferred embodiment showing aplurality of user sites (SS1-SSN) connected to a central station SW overa plurality of user telephone lines (SL1-SLN). The central station SWprovides connections between user digital computers (SC1-SCN) and a hostcomputer HC preferably configured as a BBS server. The central stationSW also provides interconnections among user sites (SS1-SSN) to provideconferencing services. Each user site includes a user station (SU1-SUN)for selecting between voice and data modes of access to the centralstation SW and the host computer HC.

Operation of the preferred embodiment of the present invention in a BBSenvironment will now be described at a high-level. A user at a user siteSS1 initiates a data mode connection between the user computer SC1 andthe host computer HC. Having established a data mode connection, theuser enters into a typical data mode session with the host computer HC.One option presented to the user by the host computer HC is to enter aconference.

There are two general conferencing modes: voice mode and data mode. Invoice mode conferencing, two or more users are interconnected via thecentral station SW. Users in a voice conference transmit and receivevoice communications signals and audible conference control signals. Theaudible conference control signals, which can be DTMF tones, forexample, are described in detail herein.

A user interface and conference control functions are also describedfurther below.

The voice conferencing mode will now be described in further detail forthe preferred embodiment. A key aspect of the present invention is theability to conduct a voice conference among multiple users whilesimultaneously viewing shared data objects, such as slides. This aspectis achieved by having the individual users initially perform filetransfers between their respective user computers (SC1-SCN) and the hostcomputer HC in order to collect and disseminate the data objectsrequired for a conference prior to the start of the voice mode portionof the conference. Thus, the host computer HC serves as a repository anddistribution point for the data objects used in a conference. Further,conducting file transfers of the data objects prior to the voice modeportion of the conference eliminates interrupting the voice mode fordownloads of data objects. For the initial file transfer of dataobjects, the respective user stations are placed in data mode and thecentral station SW is configured to pass-through data to the hostcomputer HC.

“Data objects” can be any of several information types represented inany of a multiplicity of data formats. Data objects include, but are notlimited to the following:

Object Type Description File Format image Joint Photographic .JPGExperts Group (JPEG) image graphics interchange .GIF format imagefractal image .FTC compression video full multimedia .MPG (MPEG) textstandard ASCII text .TXT rich text Microsoft rich text .RTF format CADcomputer aided many design draw drawing programs .BMP & othersspreadsheet spreadsheet programs .XLS, .WK1 & others word processingword processing .DOC & others slides slide presentation .PPT & others

The audible conference control signaling of the present invention can beused to emulate the application linking capabilities of Dynamic DataExchange (DDE) and Object Linking and Embedding (OLE) for data objectsharing within compatible applications at each user site during voiceconferencing.

Once the multiple users enter the voice modes a virtual visualconference is established simultaneously with the voice conferencewhereby display of the data objects on each user computer can becoordinated. The data objects display coordination is accomplished byhaving a designated speaker select a current data object to bedisplayed, the selection of which causes the speaker's associated userstation to generate an audible conference control signal. The conferencecontrol signal is transmitted in-band with voice communications signalsto the other users in the conference. The user station of each of theother users in the conference detects the conference control signalwhich then causes the locally stored copy of the data object selected bythe speaker to be displayed.

In an alternative embodiment, the equipment at each user site is adaptedfor point-to-point conferencing whereby two user sites can be connectedthrough the public-switched telephone network without passing throughthe central station SW. In this alternative embodiment, the two usersare able to conduct a voice conference while simultaneously viewingshared data objects. This aspect is achieved by having one of the twousers initially perform a file transfer with the other user so that eachuser has a copy of the data objects required for a conference prior tothe start of the voice mode portion of the conference. Again, since thefile transfers of the data objects occur prior to the voice mode portionof the conference, interruption of the voice mode to download dataobjects is avoided. When the two users in the point-to-point conferenceenter the voice mode, a virtual visual conference is establishedsimultaneously with the voice conference by coordinating the display ofthe data objects using the same in-band conference control signals asdescribed for the multipoint conferencing.

There are three forms of data rode conferencing in which users maytransmit and receive data signals. In a data collaboration mode, two ormore users are able to collaborate to perform a whiteboard function. Theusers in the data collaboration mode are connected through the centralstation SW to the host computer HC, each user having an individual datasession. In a private data file transfer mode, two users areinterconnected through the central station SW to provide for privatefile transfers between the two users without involving the host computerHC. There is also a private data broadcast mode in which two or moreusers are interconnected via the central station SW to allow a user tobroadcast a file to the other users. In the private data broadcast mode,there is no handshaking between user modems.

The data collaboration mode for the preferred embodiment will now bedescribed in more detail. As noted above, users in the datacollaboration mode are passed through the central station SW to the hostcomputer HC and conduct individual data sessions with the host computerHC. However, if the users seeking to take part in the data collaborationmode are currently in a voice mode conference, the users must beswitched into data mode before data collaboration can occur. This isaccomplished by the user computer associated with the currentlydesignated lead speaker sending a DTMF conference control signal via itsrespective user station to the other users in the conference to switchto data mode after a designated time, e.g., ten seconds. The userstations of the other users in the conference detect the conferencecontrol signal and are switched from voice mode to data mode at thedesignated time.

Once the data collaboration mode is entered and the whiteboard sessionis activated in the host computer HC, the designated lead speaker mayfreely draw upon a virtual whiteboard area using an input device such asa mouse connected to the user computer of the lead speaker. The leadspeaker's annotations to the whiteboard area are received by the hostcomputer HC and then broadcast as annotation commands to the other usersin the conference. User annotations may be overlaid upon data objectssuch as slides. The lead speaker may elect to allow inputs from otherconferees, in which case the annotation input from each additionalannotator is assigned a specific color and broadcast to the users in theconference, including the lead speaker. When the whiteboard annotationsession is over, the lead speaker sends either a conference controlsignal to deactivate the whiteboard session while keeping the conferencein data mode or a signal to return the conference to voice mode. In thepreferred embodiment, a protocol known as Remote Image Protocol (RIP) isused to control manipulation of the data objects which are stored ateach of the user computers (SC1-SCN) in a conference. A family of RIPcommands coded as DTMF conference control signals may be transmitted,for example, by the lead speaker to other conference attendees during avoice mode conference to coordinate display of selected data objects ateach of the attendees respective user computer (SC1-SCN). In a data modescenario, such as in a whiteboard session, the annotation commands maybe RIP commands coded as a series of escape (ESC) sequences. Adescription of the RIP protocol can be found in “RIP Aint User's Guide,”Telegrafix Communications Inc. (September, 1993, Version 1.54), thecontents of which are incorporated herein by reference.

Referring again to FIG. 1 to provide more details, the user lines(SL1-SLN) connect to the central station SW via a telephone network NWand terminate on a plurality of line ports (LP1-LPN). The centralstation SW includes a plurality of computer ports (CP1-CPN) which arecoupled to host computer HC via a plurality of host modems (HM1-HMN). Aplurality of through ports (TP1-TPN) on the central station SW areavailable for accessing other services and external networks describedfurther herein. The central station SW provides connections between lineports (LP1-LPN) and computer ports (CP1-CPN) and between line ports(LP1-LPN) and through ports (TP1-TPN). A switch matrix SMX in thecentral station SW provides interconnections among multiple line ports(LP1-LPN) to form conferences. Operation of the switch matrix SMX willbe described further below. The central station SW includes a controllerCL for controlling conference and switching actions in the centralstation SW. The controller CL communicates with the host computer HCthrough control/data lines HCL. The central station SW also includes arevenue generation module RG which records billing information for allconference and switching actions provided through the central stationSW.

At user site SS1, the user line SL1 connects to a user station SU1. Theuser station SU1 includes a microphone interface M1 and speakerinterface S1 for telephone access, an external interface EXT1, and anauxiliary port AUX1 coupled to an auxiliary device AD1. The user stationSU1 includes a data port ML1 which connects to a user computer SC1 via auser modem SM1. The user station SU1 is controlled through control linesCL1 by the user computer SC1 running a TSR (terminate and stay resident)program that shown.

The auxiliary device AD1 connected to the auxiliary port AUX1 can be,for example, a typical audio recording machine. Such an audio recordingmachine can be used to record the voice communications signals and DTMFconference control signals received over user line SL1 during the voicemode of a conference. This recording arrangement would allow a user toreplay and review a complete conference presentation in conjunction withthe locally stored data objects from the recorded conference.

The user computer SC1 can be any standard personal computer orworkstation having a display screen CS1 and associated memory andperipheral circuitry. The host computer HC is any standard personalcomputer workstation having a memory MEM and associated peripheralcircuitry. The host computer HC is preferably configured as, but notlimited to, an electronic bulletin board system. The host computer HCcan also be multiple workstations connected via a local area network orother bus arrangement.

Each of the host modems (HM1-HMN) and the user modems (SM1-SMN) can beany standard modem which is capable of modulating digital signals intoquasi-analog signals for transmission and demodulating quasi-analogsignals into digital signals.

Shown in FIG. 2 is a schematic circuit diagram of user station SU1. Thepaths SL1 a and SL1 b of the user line SL1 from the network NW terminateat TIP and RING terminals of the user station SU1. A mode selector 29comprising switches 20, 22, 24, 26, and 28 provides for selectionbetween voice and data modes of operation. Data port paths ML1 a, ML1 bconnect to user line paths SL1 a, SL1 b through switches 22, 24. Aloopback resistor RL for holding the connection to the user modem SM1 isprovided across data port paths ML1 a and ML1 b through switch 20. Theresistor RL is preferably 600 ohms to provide an expected terminationtowards the modem SM1. Switches 26, 28 provide connection between userline paths SL1 a, SL1 b and telephony paths 72 a, 72 b. A voiceinterface circuit 40 is coupled to telephony paths 72 a, 72 b to providetelephone voice access to the user line SL1. The voice interface circuit40 provides auxiliary ports AUX1 a, AUX1 b for connecting auxiliarydevices such as the voice recording machine noted above. Path 41 b ofthe voice interface 40 connects to telephony path 72 b through a switch30 and an opto-isolator 32 connected in series. Operation of switch 30is enabled through control line 18. The opto-isolator 32 detectsoff-hook, on-hook condition of the telephony circuit and passesdetection information on control line 34.

A DTMF encoder 42 and a DTMF decoder 46 respectively transmit andreceive the audible conference control signals. The DTMF encoder 42receives tone control information on control line 38 and passes toneoutputs on line 44 to voice interface 40. The DTMF decoder 46 isinductively coupled across telephony paths 72 a, 72 b via transformerT1. The DTMF decoder 46 signals tone detection on line 58 and passesdecoded tones on line 60.

A caller identification detector 48 is coupled to the telephony paths 72a and 72 b to provide standard caller identification information oncontrol line 62. A serial EEPROM 50 stores and maintains securityinformation regarding the user station SU1. Information passes from theEEPROM 50 over path 64. The switches (20-30) preferably are solid stateswitching devices, such as the OptoMOS® Solid State Switch LCA110manufactured by CP Clare Corporation. The DTMF decoder 46 may be, forexample, a MC145436 Dual Tone Multiple Frequency Receiver manufacturedby Motorola. The DTMF encoder 42 may be, for example, a NationalSemiconductor TP5088 DTMF Generator. The voice interface 40 may beimplemented, for example, with a Motorola MC34114 Telephone SpeechNetwork with Dialer Interface. The caller identification detector 48 maybe any one of several calling line identification devices such as aMotorola MC145447 Calling Line Identification Receiver.

Control and data signals pass between the user computer SC1 and a userstation SU1 over control lines CL1 which connect through port connector74. A manual switch 56 allows a control input 66 to be switched betweenlines 68 and 70. When manual switch 56 is in the position connectingcontrol line 66 to control line 68, the control logic circuitry 52 inresponse to control signals from the user computer SC1 controls the userstation SU1 for voice and data operation. When the manual switch 56 isin the position which connects control line 66 to line 70, the userstation SU1 is in a pass-through mode whereby signals on externalinterface EXT1 may pass through connector 76 through to port connector74. The pass-through mode allows the port connector 74 to function as aregular LPT parallel port so that a peripheral such as a printer or asatellite downlink receiver may be connected to the user computer.

In the default condition, the mode selector 29 operates in the data modeposition. A low signal on control line 12 causes switches 20, 26, and 28of selector 29 to open, thereby disconnecting the telephony paths 72 a,72 b from the user line paths SL1 a, SL1 b and disconnecting the loadresistor RL across the data port paths ML1 a, ML1 b. The low signal oncontrol line 12 is inverted by an inverter 14 to provide a high signalon control line 16. The high signal on control line 16 causes switches22, 24 to operate, thereby connecting the data port paths ML1 a, ML1 bto the user loop paths SL1 a, SL1 b. Thus, the user modem SM1 (FIG. 1)is connected to the user line SL1 for data mode operation.

A high signal on control line 12 causes the selector 29 to switch to thevoice mode. The high signal on control line 12 causes switches 20, 26and 28 to operate. The operation of switches 26, 28 connects user linepaths SL1 a, SL1 b to telephony paths 72 a, 72 b. To operate in thevoice mode, control line 18 must also be high to operate switch 30.Thus, telephony access is afforded through the voice interface 40coupled to the telephony paths 72 a, 72 b.

The operation of switch 20 due to a high signal on control line 12completes the path between data port path ML1 b and load resistor RL.The high signal on control line 12 is inverted by inverter 14 to producea low signal on control line 16. A low signal on control line 16 causesswitches 22, 24 to open, thereby disconnecting the data port paths ML1a, ML1 b from the user line paths SL1 a, SL1 b. Thus, the user modem SM1(FIG. 1) is disconnected from the user line SL1 and is placed in aloopback state. The load resistor RL across the data port ML1 causes thedata port ML1 to appear to be in an off-hook state to a user modem SM1having on-hook/off-hook detection. In addition, in order to keep theuser modem SM1 from timing out due to loss of received carrier, the usercomputer SC1 sends to the user modem SM1 a disable carrier timeoutcommand, e.g., the AT command ATS10=255.

During the voice mode, an off-hook condition is detected byopto-isolator 32 when current flows through the LED portion ofopto-isolator 32 which is coupled to telephony path 72 b through switch30. The photo-darlington portion of the opto-isolator 32 pulls theoutput line 34 low when current is detected.

Shown in FIG. 3 is a schematic block diagram of the central station SW.The switch matrix SMX comprises a plurality of horizontal and verticalrails (L1-LN) interconnected through a number of crosspoint switches.The minimum number of crosspoint switches required for interconnectionis determined according to the integer value N*(N−1)/2, where N is thenumber of line ports. In a preferred embodiment, the number of lineports is 16; however, this is noted by way of illustration and not as alimitation of the invention. Each of the line ports (LP1-LPN) isconnected to the switch matrix SMX through a switching arrangement asshown in FIG. 4. The TIP (LP1 a) and RING (LP1 b) of a line port LP1from the network NW (FIG. 1) are connected through a pair of switches(108 a, 108 b) and across an isolation transformer T2 which couples ACsignals between the line port LP1 and rail L1 of the switch matrix SMX.The rail L1 connects to other rails (L2-LN) through the crosspointswitches (S12-S1N).

Referring again to FIG. 3, the computer ports (CP1-CPN) have paths (CP1a, CP1 b-CPNa, CPNb) which connect to respective line ports (LP1-LPN)through switches (102-1-102-N). A resistor R1 and switch 104-1 in seriesacross computer port paths (CP1 a, CP1 b) provides a loopbacktermination to hold a connection to the computer modem HM1 in the samemanner as described above for the user modems. This loopback terminationis repeated on each of the other computer ports (CP2-CPN).

A plurality of DTMF encoder/decoder circuits (TG1-TGN) are coupled torespective rails (L1-LN) for transmitting and receiving audibleconference control signals to and from respective user stations(SU1-SUN) (FIG. 1). The through ports (TP1-TPN) are connected torespective line ports (LP1-LPN) through switches (106-1-106-N). All ofthe switches and DTMF encoder/decoder circuits in the central station SWoperate in response to control signals from the controller CL. Theswitches preferably are solid state switching devices, such as theOptoMOS® Solid State Switch LCA110 manufactured by CP Clare Corporation.The central station includes a subconferencing circuit SCF which passesattenuated voice and DTMF signals from a main conference to asubconference. The subconference comprises a subset of the mainconference attendees who may drop into the subconference to conduct aprivate conversation while still receiving the main conference voice andDTMF signals. In the subconference circuit SCF, the through ports(TP1-TPN) are connected to a multiplexer MX. The through port associatedwith the main conference is selected via the multiplexer MX and fed intoamplifier AP which attenuates the main conference signal by anappropriate amount, preferably 20 to 30%. The attenuated output isswitched via a demultiplexer DX to the through port associated with thesubconference to be mixed with the subconference voice signals. Insubconferencing operation, the appropriate switches (106-1 to 106-N) areoperated to connect the main and subconference through ports to theappropriate rails (L1-LN).

Virtual Conference User Interface

The user interface of the conferencing system of the present inventionwill now be described. The virtual visual conferencing aspect supportsfunctions that one would find in a real world conference, including:reception area, information folders, conference room, overhead projectorand screen, speakers, and attendees.

Initially a user establishes a data mode session with the host computerHC and selects a conference room option from a conference menu providedby the host computer HC. The user's screen then displays arepresentation of a conference reception area as shown in FIG. 5. Aconference reception area screen 200 includes several functional areasor icons which are activated via a mouse or keyboard selection. Areceptionist icon 202 provides a help function for new users of theconference interface and a reservation function for reserving conferencerooms for later conferences. In addition, the receptionist icon 202provides an announcement/messaging function for announcing arrivals anddepartures during conferences and for informing attendees of incomingmessages. A photocopier icon 204 provides a file transfer functionwhereby conference presenters upload files containing data objects whichare then made available for conference attendees to download throughactivation of a file folder icon 206. The downloaded data objects, suchas slides, are then available for simultaneous viewing during subsequentvoice conferences.

A payphone icon 208 provides a telephone function for allowing a user toswitch to voice mode and dial an outside line either via a through port(TP1-TPN) or via an unused line port (LP1-LPN) on the central stationSW. A table icon 210 provides a periodicals function whereby aconference attendee waiting for a conference to begin can access aninformation source, such as an electronic newspaper. A conference roomdoors icon 212 provides access to a conference room area represented bya conference room screen 220 as shown in FIG. 6. Other functional iconsmay include a conference schedule icon to provide conference informationsuch as topic, speakers, room number, scheduled date and time, andmeeting description.

Referring again to FIG. 5, to reserve a specific conference, the userselects the receptionist icon 202 via a mouse or keyboard input device.The user then enters relevant information regarding the conference, suchas conference date and time, topics, approved speakers, and attendees.The user then receives a conference room number which serves to confirmthe reservation.

Between the time the reservation has been made and some period beforethe conference is due to begin, e.g., twenty minutes, all conferencepresenters, including the lead speaker, may submit any slides, graphs,prepared text, or other data objects to be used in the scheduledconference. To submit such data objects, a presenter at the conferencereception area screen 200 selects the photocopier icon 204. Thepresenter enters appropriate conference identification information andthen performs a data mode file transfer from the respective usercomputer SC1 to the host computer HC. The data objects are then combinedwith any other data objects submitted for the same conference and thecombined data objects are represented by the folder icon 206 in thereception area screen 200. Each modification made by a presenter topreviously submitted material is indicated by a revision letter on thefolder icon 206. When the lead speaker and all other approved presentershave “signed off” on their respective contributions, the folder icon ismarked “FINAL”, which signifies to conference attendees that they areretrieving the correct and complete version of the data objects for theconference.

At conference time, the lead speaker selects the conference room doorsicon 212 on the reception area screen 200 and is then presented with theconference room screen 220 (FIG. 6). The lead speaker and the attendeesare each presented with conference information on their associatedcomputer screens (CS1-CSN), including a visual depiction of theconference room and function buttons for activating certain overhead andvoice/data functions. In the visual depiction of the conference room,the lead speaker and attendees are represented at individual chairs 222positioned around a conference table 224. The visual depiction of theconference room will automatically adjust to accommodate as manyattendees as are present. An overhead projector screen area 226 iszoomed in when the presentation begins to display the stored dataobjects in a sequence selected under the control of the lead speaker. Aconference room doors icon 228 provides access to the reception areascreen 200 and allows a conference attendee to leave the conference. Atelephone icon 230 provides a telephone function for allowing voiceconference attendees to “patch-in” an outside line either via a throughport (TP1-TPN) or via an unused line port (LP1-LPN) on the centralstation SW.

When the lead speaker elects to begin a presentation, an overhead viewscreen 240 is displayed on computer screen CS1 as shown in FIG. 7. Theoverhead view screen 240 includes a conference display area S and aconference control area CA. In the conference display area S, locallystored data objects such as slides are presented. The conference controlarea CA includes software-controlled conference function buttons, someof which are available only to the lead speaker. The conference functionbuttons can include, for example, sequential slide movement buttons Aand B (forward and reverse respectively), random slide access buttons(1-N), refresh slide button G, go digital directive button C, go voicedirective button D, leave conference button F, mute control button I,dumb control button J, lead speaker selection button H, and whiteboardannotation button E. Other conference functions can include gaincontrol, whisper sub-conferencing, and a kick out function. Examples ofthese conference functions are described in more detail herein.

Conference Control Signals and Functions

The conference control signals corresponding to conference commandscomprise a series of opcodes implemented by DTMF tones in a format shownin FIG. 8. The opcode format comprises a preamble field 252, an opcodeclass field 254, an opcode number field 256, a routing address field258, and a user address field 260. The preamble field 252 consists of asingle DTMF hexD tone.

The opcode class field 254 comprises a single DTMF tone to indicate upto 15 classes of opcodes. The opcode number field 256 comprises two DTMFtones to indicate up to 225 opcodes per class. The routing address field258 and the user address field 260 are optional, depending upon theopcode used. The routing address field 258 can be from zero to eighttones in length and is used to indicate a particular central station ina network of central stations of the present invention as describedfurther below. The user address field 260 can be from zero to eighttones in length and is used to indicate a particular line port of thecentral station indicated in the routing address field 258.

The opcode tone duration is defined on a conference by conference basis.Initially, the system attempts a tone duration of 40 ms and increasesthe duration in increments of 10 ms, up to a duration of 100 ms, until aduration is reached that satisfies all conference participants.

The conference control opcodes are illustrated by, but not limited to,the protocol records in the following table:

Command Name Class Origin Destination Opcode Format use_payphonetelephony user Host computer and central station hang_up telephony userCentral station D001 digital_to_voice mode user Host computer andCentral station end_conference mode speaker Central station and userstations D101 go_digital_self mode user n Central station D111ngo_digital_all mode speaker Central station and user stations D110go_digital n mode speaker User station n D112n kick_out n mode speakerUser station n D121n leave_conference_self mode user n Central stationD131n mute_user n environment speaker User station n D211n dumb_user nenvironment speaker User station n D221n hear_user n environment speakerUser station n D222n speak_user n environment speaker User station nD212n show slide x environment speaker User stations D231xprivate_show_slide xn environment speaker User station n D232xn refreshenvironment speaker User stations D240 turn_floor n environment speakerUser station of new speaker n D251n whisper n environment user Centralstation and user station n D261n return_whisper n environment user nCentral station D262n whiteboard environment speaker Central station anduser station(s) D270 turn_floor external rn routing speaker User stationn on central station r D311rrn go_digital rn routing speaker Userstation n on central station r D321rrn kick_out rn routing speaker Userstation n on central station r D331rrn mute_user rn routing speaker Userstation n on central station r D341rrn dumb_user rn routing speaker Userstation n on central station r D351rrn hear_user rn routing speaker Userstation n on central station r D352rrn speak_user rn routing speakerUser station n on central station r D342rrn whisper rn routing user Userstation n on central station r D371rrn

Control Procedures

The procedure to activate an individual user station SU1 (FIG. 1) isillustrated by the flow chart shown in FIG. 9. The procedure begins atstep 300 when the TSR program is loaded into the user computer. The TSRpolls the parallel ports of the user computer at step 302, looking forvalid information from EEPROM 50 (FIG. 2). If the TSR does not recognizea valid user station at step 304 based upon the information stored inthe EEPROM 50, the TSR aborts at step 306. If a valid user station isrecognized at 304, the TSR enables the user station for data modeoperation at step 308 by causing control line 12 (FIG. 2) to go low.Once the user station is in the data mode, the user can then dial thehost computer at step 310. Having connected to the host computer, theuser at step 312 selects an application to run on the host computer,e.g., conferencing and voice services.

In general, the TSR monitors the user modem COM port for data signalswhich are represented by simple ASCII character strings. The TSR willfilter this data from the user and act upon it immediately. The TSR alsomonitors the user parallel port for signals from the user station.

A description of several of the conference control procedures possiblewithin a conference will now be provided. The procedure for placing allthe conference attendees into voice mode is illustrated by FIG. 10.Starting at step 320, the users are connected in a conference and are indata mode. The lead speaker may select a go_voice icon at step 322 toinitiate the procedure. At step 324, the host computer broadcasts thedigital go_voice command to all the conference attendees. The TSR ateach attendee user computer filters the command at 326 and instructs theuser station to switch to voice mode at step 328. At the same step, thehost computer communicates with the controller CL of the central stationSW (FIG. 1) to interconnect the conference attendees in voice mode.

The procedure for coordinating the simultaneous viewing of data objects,or slides, is illustrated in FIG. 11. The procedure begins at step 340with the users connected in a conference. The lead speaker selects theslide icon at step 342. The TSR determines whether the conference is indata or voice mode at step 344. If the conference is in data mode, theslide command from the lead speaker is broadcast to all conferenceattendees by the host computer at step 346. If the conference is invoice mode, the speaker's TSR filters the slide command at step 348 andconverts the command to a show_slide_n opcode at step 350. The TSRinstructs the user station to send the opcode via the DTMF encoder 42(FIG. 2) at step 352. The opcode tone sequence is broadcast to attendeesthrough the central station SW (FIGS. 1, 3) at step 354. At eachattendee user station, the DTMF decoder 46 (FIG. 2) detects the opcodetone sequence at step 356. At step 358, the TSR of each attendeeinstructs the user computer to display slide n. Thus, although data modeactions between users and the host computer follow a client/servermodel, in voice mode, many peer-to-peer events take place between usersfor efficiency and simplicity.

The procedure for conducting a whiteboard annotation session isillustrated in the flow chart of FIG. 12. Beginning at step 370 with theusers connected in a conference, the speaker may select the whiteboardicon at step 372. The TSR determines whether the conference is in voiceor data mode at step 374. If the conference is in data mode, the hostcomputer broadcasts the speaker's annotation commands to all attendeesat step 376. If the conference is in voice mode, the conference must beswitched over to data mode before annotation can begin. The TSR of thespeaker filters the whiteboard command at step 378 and converts thecommand to a whiteboard opcode at step 380. At step 382 the TSRinstructs the user station to send the opcode via the DTMF encoder. Theopcode tone sequence is broadcast to the conference attendees throughthe central station SW (FIG. 3) at step 384. The opcode tone sequence isdetected at each user station at step 386. The TSR of each attendeeinstructs the respective user station to switch to data mode at step388. At this point, the central station SW also switches to data mode.Annotations from the speaker are then broadcast to the other attendeesvia the host computer at step 376. In a case where one or more attendeesare also given the opportunity to annotate, the annotations of theseattendees are broadcast in the same manner.

The procedure for allowing an attendee to leave a conference isillustrated in the flow chart of FIG. 13. Beginning at step 400 with theusers connected in a conference, an attendee may select theleave_conference icon at step 402. The attendee's TSR determines at step404 whether the conference is in voice or data mode. If the conferenceis in data mode, the attendee is returned to the reception area screen200 (FIG. 5) at step 406. IF the conference is in voice mode, theattendee's TSR filters the leave_conference command at step 408 andconverts the command to a leave_conference_self opcode at step 410. TheTSR instructs the user station to send the opcode via the DTMF encoder42 (FIG. 2) at step 412. The opcode tone sequence is detected by a DTMFdecoder TGi (FIG. 3) at the central station SW at step 414. From step418, the attendee's TSR switches the user station to data mode whilesimultaneously the attendee's line port on the central station SW isswitched to data mode. At the data mode, the attendee is returned to thereception area screen at step 406.

The teleconferencing system of the present invention can also beconfigured in a network arrangement as shown in FIG. 14. Two centralstations SWa, SWb are shown connected through a frame relay network FR.Two central stations are shown for purposes of example and not as alimitation, i.e., any number of central stations may be interconnectedthrough network FR. The frame relay network FR includes connections toInternet network IN and a Ku-band uplink server UL. The uplink server ULin turn connects via a satellite network KN to a Ku-band receiver KRlocated at user site SSN and connected to user station SUN.

The network arrangement provides for sharing of communications resourcesamong cooperating BBS systems. Thus, for example, a conference can beconducted among user sites connected across such a network arrangement.A second example is where a first BBS system, such as host computer HCa,has several voice recognition servers. Users associated with a secondBBS system, host computer HCb, can then be routed via the frame relaynetwork FR to central station SWa and host computer HCa in order toaccess a voice recognition application.

A third example is where the uplink server UL connected to the framerelay network FR performs high-speed information downloading to receiverKR. Many telecommunications service providers want to be able to deliverbi-directional data at high bandwidths for multimedia applications.However, in most applications it is more important to deliver largeamounts-of data to the end user (downloaded), while very little dataneeds to be sent back to central file servers from end users (uploaded).With the satellite networking arrangement of the present invention shownin FIG. 14, users may receive high-speed file downloads or real-motionvideo via satellite rather than over narrow bandwidth telephone lines.In operation, the user at user site SSN may request a large filedownload from the local BBS, host computer HCa. Host computer HCa queuesup the file from its internal file storage, or from the Internet IN. Therequested file is then routed over the frame relay network FR to theuplink server UL with the user address information. The file istransmitted over the Ku band satellite network KN with user addressingand encryption and received by receiver KR. The received file is thenrouted through user station SUN to the local digital computer at usersite SSN. Billing information for the file transfer is forwarded alongwith file transfer confirmation to the host computer HCa after achecksum verification indicates that the file was received error-free.

A fourth example combines satellite technology for real-time multimediainformation delivery with user/host computer communications to form acomplete multimedia system. Referring again to FIG. 14, a user at usersite SSN may request to see, for example, a one minute productpresentation. One minute of compressed video occupies approximately 12Mb. The host computer HCa transmits 2 Mb frames every ten secondsthrough the frame relay network FR and the satellite network KN to theuser receiver KR. Each new frame can be loaded directly to the on-boardmemory of the user digital computer at user site SSN for audio/videoplayback. Real-time user feedback is communicated between the user andthe host computer HCa via the modem connection.

EQUIVALENTS

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims.

1. A method comprising: providing a plurality of interconnected usersites; transmitting a data object from at least a first user site to atleast a second user site between any user sites of said plurality ofinterconnected sites; locally storing said transmitted data object bythe at least second user site; and retrieving said locally stored dataobject by a user interface as directed by a signal transmitted by anyuser site of said plurality of interconnected sites.
 2. The method ofclaim 1, wherein the data object is at least one of a common data objectand a private data object.
 3. The method of claim 1, wherein the dataobject includes an ASCII character.
 4. The method of claim 1, whereinthe data object includes image data.
 5. The method of claim 1, whereinthe plurality of user sites is interconnected via a wide area network,wherein the wide area network comprises an Internet network.
 6. Themethod of claim 5, wherein the plurality of user sites is interconnectedvia a wide area network, wherein the wide area network comprises asatellite network.
 7. The method of claim 1, further comprisingproviding a central site to which at least two user sites of saidplurality of interconnected user sites are connected.
 8. The method ofclaim 1, wherein retrieving said locally stored data object by a userinterface as directed by a signal transmitted by a user site of saidplurality of interconnected sites, further comprises transmitting saidsignal through point-to-point conferencing.
 9. The method of claim 1,wherein transmitting a data object further comprises transmitting saiddata object from said at least a first user site to a central site,which central site in turn distributes said data object to said at leasta second user site prior to conferencing between any user sites of saidplurality of interconnected sites.
 10. A method comprising: providing aplurality of interconnected user sites, wherein at least a first usersite and a second user site of said plurality of user sites;transmitting a data object from at least said first user site to saidsecond user site of said plurality of interconnected sites; locallystoring said transmitted data object by at least one of the first usersite and the second user site of the plurality of user sites; andforwarding said data object locally stored by at least one of the firstuser site and the second user site of the plurality of user sites to atleast another of said user site as directed by a signal transmitted byany user site of said plurality of interconnected sites.
 11. The methodof claim 10, wherein the data object is at least one of a common dataobject and a private data object.
 12. The method of claim 10, whereinthe data object includes an ASCII character.
 13. The method of claim 10,wherein the data object includes image data.
 14. The method of claim 10,wherein the plurality of user sites is interconnected via a wide areanetwork, wherein the wide area network comprises an Internet network.15. The method of claim 10, wherein the plurality of user sites isinterconnected via a wide area network, wherein the wide area networkcomprises a satellite network.
 16. The method of claim 10, furthercomprising transmitting another data object point-to-point from a usersite to another user site prior to conferencing between any user sitesof said plurality of interconnected sites.